Change-speed gearing for power-propelled vehicles.



F. H. ROYCE.

CHANGE SPEED GEARING FOR POWER PROPELLED VEHICLES.

APPLICATION FILED gum: 6. 1914.

1,149,408. Patented Aug. 10, 1915.

WITNESSES |NVENTQR Amy.

UNITED STATES PATENT OFFICE.

FREDERICK HENRY ROYCE, OF DERBY, ENGLAND.

CHANGE-SPEED GEARING- FOR POWER-PROPELLED VEHICLES.

Specification of Letters latent.

Patented Aug. 10, 1915.

Application filed June 6, 1914. Serial No. 843,552.

and it has for its object generally to over come some of thedifficulties which are experienced 1n providing an eflicient gearing ofthis type and specifically to provide a second speed ratio of higherefliciency than has hitherto been possible with compounded ears.

6 I attain the object of the pres ent invention by the constructionshown in the acaccompanying drawing in which the essential feature isthe driving of the accelerating train from the driving element and notas previously from the driven element of the gearing.

The gearing consists essentially of two epicyclic trains hereinafterreferred to as the main train and the accelerating or secondary train.The sun wheels a and b of the acceleratin and main trains respectivelyare both fixe on the driving element 00, said element in theconstruction shown being formed in two parts forconvenience, both partsbeing rigidly fixed together and one of them being the crank shaft ofthe prime mover. The sun wheel I) of the main trainwhich gives the firstor lowest speedengages with planet pinions 0 revolubly mounted on pins 0carried by a planet disk 0, said planet disk being mounted on or formingpart of the driven element a. The internally toothed annulus d of themain train, with which the pinions c mesh, is formed in one with or isrigidly connected to the planet disk 6 of the accelerating train and iscapable of being held stationary by the brake bandit. The planet disk 6of the accelerating train carries pins c on which are revolubly mountedthe planet pinions e which mesh with the sun wheel a. The internallytoothed annulus f of the accelerating train, which is loosely mounted onthe driving element w, is capable either of being'held I stationary bythe brake band It or of being connected to the driving element x by thefriction clutch m, said clutch being held out of engagement for allspeeds except the top or directdrive.

The first or lowest speed is obtained by tightening the brake band It onthe annulus (Z whereby the planet disk 0 and the driven element 2 arecaused to rotate at a predetermined relatively lower speed than thedriving element m, the speed of z-being in the gearing illustratedapproximately .36 of the engine speed.

The second speed is obtained by tighten- The annulus (Z Wlll now receivemotion from this acceleratmg train through the planet disk 6 and thusthe planet disk 0 and the driven element 2 will have a relatively higherspeed than they had on the first. gear when the annulus d was heldstationary, the speed of .2 in this case being approximately .6 of theengine speed.

The third speed or direct drive is obtained by engaging the clutch m,which latter couples the annulus 7 to the driving element :0, the brakebands It and 72 being free. The sun wheel a thus becomes coupled to theannulus f, which thereby affects a couple between the annulus d andthesun wheel 6, whereby a couple is affected between the driving and drivenelements and the main and accelerating trains are caused to rotate enbloc.

Vith this method of obtaining the direct drive the driving torque on theclutch is considerably less than the engine torque, and said drivingtorque is reduced to a greater extent than has hitherto been possiblewith other arrangements of epicyclic gearing, which enables a frictionclutch of light construction, easy manipulation, quick and effectivedisengagement to be employed. This reduction in torque on the clutch maybe explained as follows :First, there is a reduced torque on the annulusof the main train, the torque being inversely proportional to therelative speeds of the annulus and planet disk when the sun wheel isheld stationary. Secondly, this torque is further reduced by theaccelerating train before the clutch is reached, and thus the totalreduction in torque on the clutch is considerable and amounts toapproximately half the engine torque.

f ing the brake band is on the annulus 7', the

brakeband it being free.

What I claim as my invention and desir to secure by Letters Patent is 1.In change speed gearing of the epicyclic type, the combination of atrain comprising a sun wheel fixed on the driving element, a disk indriving connection with the driven element, planet pinions carried bysaid disk and gearing with said sun wheel, and an internally toothedannulus freely mounted in relation to the driving element and gearingwith the planet pinions; of a second or accelerating train comprising asun wheel fixed on the driving element, a disk in driving connectionwith the annulus of the first train, planet pinions carried by said diskand gearing with said sun wheel, and an internally toothed annulusfreely and a freely mounted internally toothed an nulus gearing withsaid planet pinions; of an accelerating train comprising planet pinionscarried by a disk in driving connection with the annulus of the maintrain, a sun wheel in driving connection with the sun wheel of the maintrain, and a freely mounted internally toothed annulus gearing with saidplanet pinions; and of means for holding the annulus of the acceleratingtrain stationary whereby theplanet disk of the auxiliary train and withit the annulus of the train is caused to rotate thereby giving a speedratio between the driving and driven elements of higher value than theratio which is rendered operative by holding the annulus of the maintrain stationary.

3. In a change speed gearing of the epicyclic type, the combination of amain gear train comprising a sun wheel fixed on the driving element, adisk in connection with the driven element, planet pinions carried bysaid disk and gearing with said sun wheel, and an internally toothedannulus freely mounted in relation to the driving element and gearingwith the planet pinions; of an accelerating train comprising a sun wheelfixed on the driving element, a disk in driving connection with theannulus of the first train, planet pinions carried by said disk andgearing with the sun wheel,

and an internally toothed annulus freely mounted in relation to thedriving element and gearing with said planet pinions; of means forcouplingthe annulus of the accelcrating train to the sun wheel of saidtrain; of means for coupling the disk carrying the planet pinions of themain train to the driving element; and of means for holding the annulusof each of the trains stationary.

In testimony whereof I have signed my name in the presence of twosubscribing witnesses.

FREDERICK HENRY ROYCE; Witnesses:

GONSTANCE POPPLETON, MAURICE OLLEY.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. 0.

